Morphogenesis and pattern formation are vital processes in any organism, whether unicellular or multicellular. But in contrast to the developmental biology of plants and animals, the principles of morphogenesis and pattern formation in single cells remain largely unknown. Although all cells develop patterns, the giant ciliate Stentor coeruleus provides unique features of large size, highly reproducible patterns and cellular landmarks, and a remarkable ability to heal wounds that allows microsurgical approaches of a type normally seen in embryology. Stentor was a popular model organism for exploring the mechanism of cellular morphogenesis and regeneration but was never developed as a molecular model system. We have now sequenced the Stentor genome and developed a method for testing gene function by RNAi. We propose to use these genomic tools to test a set of hypothesis about how the cell cortex and nuclear work together to direct pattern formation during cell development and allow regeneration of cellular structures following surgical removal. We expect our studies to open a new window onto the mechanisms by which cells form patterns and develop complex structures, which is a universal problem throughout all of biology.